Search for dissertations about: "Doppler tomography"

Showing result 1 - 5 of 19 swedish dissertations containing the words Doppler tomography.

  2. 1. Studies of vector tomography

    Author : Kent Stråhlén; Matematik LTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Doppler tomography; Doppler Radon transform; local tomography; vectorial k-plane transform; vectorial Radon transform; k-plane transform; Radon transform; tomography; vector tomography; Mathematics; Matematik;

    Abstract : The motivation to study the kind of problems appearing in this thesis has been ultrasound measurements of flows, from which velocity spectra along lines can be determined. These velocity spectra can mathematically be described by a new non-linear transform, here called the Doppler Spectral Transform (DST). READ MORE

  4. 2. Experimental verification of tomographic measurement methods in ultrasound

    Author : Monica Almqvist; Avdelningen för Biomedicinsk teknik; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; airborne.; high resolution; characterization; tomography; light diffraction; doppler; ultrasound; vector tomography; Instrumentation technology; Mät- och instrumenteringsteknik;

    Abstract : This thesis describes two different measurement methods applied to ultrasound. The first method, Ultrasound doppler vector tomography, uses ultrasound to measure blood flow and the second method, Light diffraction tomography, measures the pressure field in an ultrasound beam with laser light. READ MORE

  5. 3. Laser Doppler Flowmetry and Imaging: Methodological Studies

    Author : Siv Bornmyr; Malmö Institutionen för kliniska vetenskaper; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Clinical physics; digital photography.; cold intolerance; sympathetic nervous system; flow cessation external pressure; skin temperature; thermography; skin blood flow; laser doppler imaging; Laser doppler flowmetry; radiology; tomography; medical instrumentation; Klinisk fysiologi; radiologi; tomografi; medicinsk instrumentering;

    Abstract : Laser Doppler flowmetry (LDF) and laser Doppler imaging (LDI) are modern methods for non-invasive and continuous assessment of skin blood flow. The techniques are based on the phenomenon that monochromatic light transilluminating a perfused tissue is spectrally broadened owing to scattering by moving blood cells. READ MORE

  6. 4. Power Doppler - Principles and Potential Clinical Applications

    Author : Anders Nilsson; PG Lindgren; Torbjörn Andersson; Uppsala universitet; []
    Keywords : MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Radiology; Ultrasonography; Doppler studies; Power Doppler; Volume flow; Radiologisk forskning; Radiological research; Radiologisk forskning;

    Abstract : The purpose of this work was to: a) Determine whether the amount of colour in a power Doppler image is dependent on the angle between the examined vessel and the soundbeam and/or on the velocity of the flow within the vessel; b) Investigate if a dependency on flow velocity could be used for the detection of volume flow differences and c) Define clinical applications utilising the improved sensitivity to low flow of PD.In the experimental studies (study I and II) a silicon tube in a water bath was insonated, the insonation angle and the volume flow changed and the resulting images stored, transferred to a personal computer and analysed with regard to the amount of colour present in the image. READ MORE

  7. 5. Inverse Problems in Tomography and Fast Methods for Singular Convolutions

    Author : Fredrik Andersson; Matematik LTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik; Unequally spaced FFT; Integral transforms; Singular integrals; Lippmann?Schwinger equation; Helmholtz equation; Inverse problems; Fast Gauss transform; Fast summation; Convolution; Radon transform; Tomography;

    Abstract : There are two, partially interlaced, themes treated in this thesis; inverse problems of tomographic type and fast and accurate methods for the application of convolution operators. Regarding the first theme, the inverse problem of Doppler tomography is considered and the Doppler moment transform is introduced for that purpose. READ MORE